Our research has led to the development of an improved caloric vestibular testing method whereby stimulus intensity can be conveniently controlled to preselected values while also reducing the time required to perform the test. Application of the procedure to normal subjects and patients has confirmed the theoretical expectations and practical advantages of the method. However, further research is needed to refine the method and equipment used to perform the test and to explore the diagnostic capacity of the new procedure in a clinical setting. We propose to study: (1) the relationship between caloric response intensity and the dimensions and condition of the associated temporal bone, (2) the relative merits of using air vs. water to perform aural irrigations, (3) alternative methods for detecting and scoring the response to caloric stimulation, and (4) further modifications and refinements of the irrigation timing and strategy used in the new temperature-switching caloric test. The finalized version of the new test procedure will then be administered to normal subjects and to patients with identified diseases, in order to establish normal values and to reveal abnormal patterns which may be associated with specific disease states.